A client is prescribed ethinyl estradiol and drospirenone (Yasmin) for to treat postmenopausal vasomotor symptoms. The nurse instructs the client to monitor for which of the following that may indicate a serious adverse complication?

The correct answer is B: Pain, redness, and swelling in the calf. This symptom may indicate deep vein thrombosis (DVT), a serious adverse complication associated with hormonal therapy like ethinyl estradiol and drospirenone. DVT is a blood clot in a deep vein, commonly found in the calf, and can lead to life-threatening complications if not treated promptly. Insomnia (choice A), sedation (choice C), and indigestion (choice D) are not typically associated with Yasmin and are less likely to indicate serious adverse complications in this context.